Feels Like Home
by phasha18
Summary: Agatha has been gone a long time, Isabelle and Jace don't remember her at all. Alec remembers everything about her and made a promise that he would say nothing unless she came back now she's back to help or at least guide them. Temporarily on Hiatus, until further notice.
1. Chapter 1

**Disclaimer:** _I don't own the characters from Cassandra Clare's series the Mortal Instruments. They belong to her, however I do own Agatha. This is a mixture of the books - combining all them to some degree._

 _ **Feels Like Home**_

 **Chapter 1.**

Jonathon 'Jace' Wayland lay awake in his bed, he was thinking back to when he was a child and realised that some parts of his childhood were completely unknown to him. In a way he wanted to know more, but at the same time he didn't there was always a reason that things were hidden. Clarissa 'Clary' Fray was asleep in the room that she had been assigned, which was a few doors down from Jace. Alexander 'Alec' and Isabelle 'Izzy' Lightwood were both awake and asleep in their respective rooms. None of them could sense what was happening just outside of their walls.

Outside the walls a young woman no older than twenty-one stood outside, there was demons attempting to enter into the institute which was on sacred ground, she was there casting runes to deflect them.

'Hodge, I haven't been here in a long time and I know you know who I am,' a message played on Hodge's phone, although the older man was dead his phone was still on in his office.

Alec had decided on going for a walk to clear his head. He was the oldest of the shadow hunter children. He remembered more than what he let on of what happened to Jace, he had been allowed to on the promise that he would never tell anyone. Alec could hear the young woman's voice coming from inside the room.

"I know that voice," Alec thought to himself as he stopped when he came to Hodge's office, he walked over to the large window and looked out. "Aggie?" he stepped away from the window when he saw her standing outside being attacked. He ran to Jace's room and then to Isabelle and Clary, he was slowly beginning to trust the young girl. "Demons, attacking," with that he ran outside and to the gate, opening it and letting the older girl in. "Where have you been Aggie?" Alec questioned as the teens began to fight.

"Around, and now is not the time – go back inside," Agatha 'Aggie' Wayland said as she pulled a witchlight out of the back of her pants. Like Jace, her last name had been changed when she was little but she still remembered her birth-name.

After a few minutes Aggie had managed to get the downworlders and demons to stop attacking the institute and had made her way inside, where she was greeted not so kindly by Maryse Lightwood. The three teenagers – Izzy, Jace and Clary watched warily as Alec hugged the older girl. It was one of the first signs of affection the older teen had shown anyone.

"Look, I know that I told you a long time ago that I wouldn't return, but there was something nagging at me. Aunt Maryse, please tell me that you've looked after Jace?" Aggie turned to Maryse as she spoke, Alec hadn't let go of her yet – he almost didn't want to. "Alec, I do need to breathe you know,"

"Oh...sorry..."Alec reluctantly let go, Izzy looked at her brother curiously, she wasn't sure who the older girl was and why her brother seemed so attached to her. "Jace is fine, stubborn."

"You haven't told him have you?" Aggie questioned, she wanted to get back to the task at hand but also needed to know just what Jace had been told.

"I haven't and you need to know something else..." Alec muttered the last part of his sentence.

"Jace, hold out your arm. I'd like to do something," Aggie said smiling gently at the younger boy and looking to Alec, Izzy and Clary. "My name is Agatha – but everyone calls me Aggie," she smiled at them as she pulled out her _stele._ Jace held out his arm to her, he wasn't sure exactly why he was doing it. A few seconds later Aggie drew two small runes on the inside of Jace's arm – one for remember/recall and one that he didn't recognise. "Alec you may want to stand close to him for just a moment,"

"What did you just do? What runes are they?" Clary asked, she was curious as to what was happening and had stepped closer to Jace in order to see. "I know that one being 'remember' but what's this one?"

"You're right the first is remember/recall, but the second is newly created it means family and past...it only really works when..." Aggie paused, there was something about Clary. "Sorry, but what was your name?"

"Her name is Clarissa Fairchild," Maryse told her, the older woman thought about telling that she was Jace's sister – but thought more of it. "She's Valentine and Jocelyn's daughter,"

Jace started to pale as the runes that Aggie had drawn started to take effect. Alec steadied his brother as he started to sway. Aggie stayed where she was, she needed Jace to concentrate on her. Izzy and Clary stared at the three of them, as Maryse moved between the two teenage girls.

"Take a deep breath Jace, and relax," this time it was Alec telling him what to do. "She knows what she's doing," Jace tried to relax and do what Alec told him but it was hard, he was slightly scared but didn't want to show.

"Clary asked what the second rune I drew was, Aunt Maryse would you tell her?" Aggie questioned watching as Alec guided Jace over to the nearest couch.

"The second rune means family," Maryse told her, she knew that Clary didn't have much knowledge of the runes at all. In fact she was surprised that she even knew the rune for remember. "One that was told to Aggie and only Aggie long ago,"

 _Aggie stood outside the manor house, crouched down in front of her younger brother Jace and his best-friend Alec.'Jace, I have to go away for a little while. But I'll be back when you need me the most,' a then thirteen year old Aggie had said to a then 8 year old Jace before she had turned to Alec. 'Look after my little brother for me,' Alec had just turned 10 years old – he nodded he knew that it must have been important._

 _'Why do you have to go away Aggie?' Jace had questioned wrapping his arms tightly around her neck. 'I don't want you to go!'_

 _'Because I need to go away to study. I won't be far...' Aggie had replied reciprocating his hug before pulling away from him. 'If you go to your room there's a surprise waiting for you,' she had told him, but hadn't specified what it was. 'Alec I need you to promise me something. You need to look after Jace. I've told your mother – well requested it, that she have someone temporarily erase me from Jace and Izzy's memories...' Jace had come running back outside laughing – his sister had drawn him a picture of one of their pets. 'That's your birthday present, since you will be 9 years old soon,'_

After the rune's effects had worn off Jace, Alec looked curiously at him – wanting to know what his brother had remembered. Maryse took Izzy by the hand and pulled out her own _stele_ and drew similar runes on her daughter's arm.

"Jace, don't say anything just take it in. I need to talk to Aggie," Alec grabbed Aggie by the arm and dragged her out of the room.

"What is it Alec?" Aggie questioned, although she had her own questions.

"Jace...he thinks that Clary is his sister...we all do..." Alec said, he was uncertain of what her reaction would be.

"What do you mean Clary is his sister...?" Aggie looked at Alec raising her eyebrow as she spoke and ran a hand through her blonde hair. "There was only me and him...Alec it was always Jace and I..."

"I know...I remember, and that's why I'm so confused about this whole thing. What did Jace see?" Alec questioned, before Aggie could answer him Jace had appeared beside them and was glaring at her.

"Why did you leave me? I was eight years old!" Jace almost screamed at her, his fist clenched beside him.

"Jace, I had to. I may have been thirteen years old but there was things that I needed to do, that I couldn't do in Idris...I went to the institute in New York to talk to the Lightwoods, I knew that if anything happened to dad or you that they would take care of you," Aggie told him, she was trying to think of the best way to explain it to him. "The safest way for that to happen was to have you forget about me...for Izzy to forget, I knew if Alec knew he'd protect you and that's what he's done. I know you hate me..."

"I don't hate you...I just don't know you like I want to," Jace told her, slightly relaxing as he listened to what she had told him. "Where did you go?"

"Around a lot of places, I lived at the institute in London – went back to Idris a few times. I'm sorry I wasn't there when he died," Aggie didn't want to tell him that there father had died long before Jace was ten, or that the Inquisitor was their grandmother. "I'm not going anywhere again," within seconds Jace had wrapped his arms around her, those were the words that he had wanted to hear.


	2. Chapter 2

_**A/N:**_ _I'm writing approximately a dozen stories simultaneously so it could be a while between updates. But feel free to PM me if you want sneak peeks._

 **Chapter 2.**

By the time Izzy, Maryse and Clary had walked over to them Jace was still hugging her. Showing signs of affection to his big sister that he rarely showed to anyone, not even Clary. Izzy pulled Jace away from Aggie and wrapped her own arms around the older girl. Her mother had used the remember rune on her.

"Clary, this is Aggie...my...our sister," Jace said, Maryse looked to Clary and then at Jace and Aggie.

"In the space of a week I've found two siblings that I never knew about..." Clary said she didn't know how to react to this, as it had come so suddenly.

"How old are you Clary?" Aggie questioned, that was one thing that nobody had told her. "I know that you're younger than I, and Alec,"

"Sixteen," Clary replied, looking to the older girl as she spoke. "How old are you?"

"Twenty-one, Aunt Maryse – where's Max? He was just a baby when I left," Aggie answered, before questioning where the youngest Lightwood was.

"In his room, most likely reading one of those silly books that you send him on occasion," Maryse replied, there was no emotion in her voice. "Agatha, why did you return?"

"Valentine," was the only word that Aggie answered with – it caused the four teenagers to look at her in complete confusion. "Oh don't give me that look, I'm not one of his minions. I came back because I knew something was wrong. I've heard whispers that he was back and I needed to see for myself," Aggie told them, she hated the man – he had killed her father and Jace's.

"He's our father," Jace stated, Agatha shook her head, she had to – what else was she to say.

"Where's Uncle Lucian, there was a rumour that he lives around the area?" Clary looked straight at her, how did she know who Luke was. "I know that look, Clary. I was 5 years old when Jace was born, Lucian, or Luke as you know him has known me for as long as I can remember – which mind you is a very long time,"

"Oh...he owns a small book-store around here," Clary replied as she glanced to beside Aggie and noticed that Jace was no longer standing there.

Both Jace and Izzy had collapsed, Alec moved to pick up Jace but Aggie shook her head. Alec raised an eyebrow at her as she moved and picked up the younger boy. Alec laughed, he remembered that she had been strong – and Jace was just like her.

"Clary, Jace is my little brother, and if you're his little sister that makes you mine too," Aggie smiled at her. "Come over and help me move him to the couch, he'll be okay,"

"Are you sure? I've never seen anything...like that before...then again I haven't seen much of anything," Clary said, remembering that lately all Jace had done was protect her and yell at her. "Why aren't you using a rune?"

"They need sleep, that's the only way to help them after the memories that they witnessed," Maryse told them as she watched her son move her daughter on to one of the other couches. "Robert will want to know what you know as will the Clave,"

"Aunt Maryse," Aggie started to say as she and Clary moved Jace over to the couch and laid him down on it.

"Come with me and see mom?" Clary asked, she wasn't sure what the older girl would do. "Please?"

"How about the three of us go, when Jace wakes? And maybe we'll see Luke. I need to talk to him," Aggie smiled at her before standing up and walking out of the room she needed to clear her head and the one place she could do that was the green house.

Max had heard all of the commotion going on downstairs and had snuck down to see what was going on. Aggie had almost run straight into the nine-year-old. She looked down at him and smiled and whispered in his ear that she was the one that sent him all the little presents.

"Hi," Max pushed his glasses up his nose and looked at her, his grey eyes studying her face.

"Hi Max, the last time I saw you, you were only a baby," Aggie told him, she had to laugh as he recognised her.

"I know, my mother tells me that you're the one that sends me all the presents," Max told her, grinning as he wrapped his arms around her. "She told me that you do it because you feel guilty," he whispered the last part. Just what had he been told about her?

"Want to come up to the greenhouse with me?" Aggie held out her hand, which he took and then led the way to the greenhouse. "You know, I haven't been up here in a really long time," when they got to the greenhouse Aggie and Max went to the spiral staircase and sat down.

"Did I say something wrong?" Max asked looking at her. "Mom didn't say why you felt guilty. I asked her that one day,"

"She's right though, Max...I feel guilty about leaving when I did...it was a long time ago now though, you were only a year old – not old enough to remember me like the others," Aggie told him, she cared about him even though it was only her first time meeting him since he was a baby.

"Don't. Jace would understand, I know that I'm only nine and I don't really understand but he's older," Max rambled, nobody had known that he had overheard his parents talking to Alex one evening. "It's okay...I didn't tell him that I knew that you were his sister,"

"Thank you, Max"

Aggie smiled at him and then listened to the chime of midnight. Aggie and Max both stood up and looked around the flowers only bloomed at midnight and it was a wonderful sight in the darkest time.

The next day, Clary took both Jace and Aggie to see her mother, who she believed was both the older two's mother as well. Aggie had to pretend that Jocelyn was her mother and Jace's even though deep down she knew that she wasn't.

As time went passed by them, Jace distanced himself from both Aggie and Clary, Clary found a little solace in going and hanging out with Simon. Aggie spent most of her time talking with Izzy and Alec, he'd spent most of his time with Magnus Bane. Magnus and Aggie had shared a look one day and laughed.

The next thing they knew they were all in Idris, Simon and Luke included. Aggie had agreed to attend the meetings with the Clave as she was a Shadowhunter after all and it was in her blood. Luke was also her Uncle, more so than Maryse being her Aunt. Aunt was just what she had grown to call her, Luke was her uncle by blood.

"Mom, you need to give Jace the box – the one that you gave me and that I returned," Aggie told her mother, Amatis Herondale. Amatis had agreed with her daughter, Jace needed to know the truth about his father. Aggie was visiting with Amatis while they were there as she needed to see her.

"Does he know that you don't share the same mother?" Amatis questioned, looking at her daughter as they stood in the city of Alicante.

"Deep down he does, I think. To be honest with you mom I don't know," Aggie replied running a hand through her hair as Jace walked over to them. "Hey Jace," Aggie had found out long before that she had been raised by Valentine, along with Jace. Amatis had told her that one day when she was a child and had seen her in the city.

"Hi, the Lightwood's told me to get you...we're leaving tonight – going back to the Institute," Jace said from slightly behind the two older women. "Maryse wants to know if you're coming with us?"

"Of course she does, she doesn't want to deal by herself – after everything that's happened," Aggie told him, spinning around to face him. "Talk to Amatis, Clary is probably with her mother and Luke," Aggie left Jace staring at Amatis, she didn't dare call her 'mom' at least not until Jace knew the full truth about the blood that they shared.

"Wait, Aggie – does that mean that you are coming with us? Back to the Institute?" Jace questioned grabbing her arm before she could go too far from him.

"Yes Jace, I'm coming back. I did tell you that I was never leaving you again, didn't I?" she smiled at him pausing as she looked up at the sky that had started to glow with the witchlight stones. "And Jace, if you ever need to talk to me, about anything you can." Jace let a little smile creep onto his face before he went back and talked with Amatis, Aggie waved to her mother and then went back to the Lightwoods.

When they arrived back at the Institute, Izzy and Maryse had shown Aggie to where she would be staying. Alec and Magnus had gone off almost as soon as they had arrived – a romantic holiday they called it. Izzy continued to blame herself for the death of Max, Aggie seemed to be the only one who could get the teenage girl to sleep. She had done the same thing with Maryse, calmed her – only the only possible way to calm her was to use a rune. Jace had disappeared with Sebastien to who knows where.

"Izzy, stop it. Stop blaming yourself please," Aggie said pulling her towards her and giving her a hug. They were standing in the library with Maryse. "Aunt Maryse, I know how to track Jace...I've always known...Valentine doesn't know this, nor does Jonathan or Sebastian – whatever you call him." Aggie told Maryse what she had taught herself a long time ago.

"How did you learn?" Maryse questioned, but then thought better of it – sometimes Aggie like to surprise the older woman.

"I don't know, and that's the truth Aunt Maryse," Aggie replied closing her eyes and concentrating and getting a vague fix on where her baby brother was, she still had her arms wrapped around Isabelle as the younger girl had refused to let go.

"Mom, let her do it," Isabelle told her mother as she glanced up at Aggie.

"Izzy, I need to talk to Alec before I do anything," Aggie unwrapped Isabelle's arms from around her. "Please let me talk to him first," Aggie quickly left the room to go and find Alec. "Alec, I need your help," she had walked straight to his room and gone in even though the younger man wasn't in the Institute Aggie knew he could hear her.

"Alec, I need your help," she had walked straight to his room and gone in even though the younger man wasn't in the Institute Aggie knew that he could hear her.


End file.
